(1) Field of the Invention
Systems producing cold conditions in cooling and freezing installations, refrigeration, refrigerating machines for cooling and heating operation, refrigerating installations, refrigerating units, heat pumps, air-conditioning systems and so on.
(2) Description of the Related Art
Known forms of refrigeration are, firstly, dry expansion operation, in which the refrigerant undergoes a pressure reduction via an expansion valve and is transformed from the liquid state into a liquid/vapor mixture and then to evaporate completely into a vapor in the evaporator, to then leave the evaporator with slightly superheated vapor. This liquid to vapor transition of the refrigerant cools down a second medium by heat absorption, and, secondly, by a thermosyphon operation, in which the refrigerant is fed via an equalizing and separating vessel to the evaporator in liquid form either by means of gravity or with the aid of a pump. It is quite possible for the vapor to still contain liquid fractions at the evaporator outlet, and so there is generally no superheating of the refrigerant at the evaporator outlet.
Under practical conditions, all of these systems suffer from more or less serious disadvantages, which we eliminate by our invention, and consequently achieve considerable energy and cost savings.
Dry expansion systems have the advantage of a simple type of construction and small refrigerant contents.
The evaporator efficiency is substantially improved by minimizing the evaporator superheating.
For the compressor, however, this is disadvantageous, and correspondingly high superheating provides improved efficiency (improvement in volumetric efficiency, lubrication, etc.).